This invention relates to pipe couplings and more particularly, it relates to a band clamp for making sealed joints in closely spaced pipes.
There are various applications in which a pair of pipes are disposed in parallel, closely spaced relationship and each pipe requires a separate pipe extension to be coupled therewith. For example, in an engine exhaust system for a motorcycle, it is known to use a muffler which is provided with a pair of stub pipes extending from the end of the muffler body in closely spaced parallel relationship. In this arrangement, each stub pipe is coupled with another pipe as an extension of the conduit for the exhaust gases. In such an exhaust system, it is important to provide a sealed coupling or joint between each stub pipe and the associated pipe-extension which provides a high pull-apart strength and a good gas seal between the pipes. Preferably, the pipe joint should be easy to install and adapted for disassembly after it has been in use for a period of time.
The prior art shows various clamp arrangements for holding two or more hoses, pipes or other conduits in closely spaced parallel arrangements. The Gunn patent U.S. Pat. No. 2,012,562 granted Aug. 27, 1935 discloses a clamp or clasp for holding two flexible hoses in parallel arrangement. The Coberly patent U.S. Pat. No. 2,592,791 granted Apr. 15, 1952 and the Slaughter patent U.S. Pat. No. 2,621,384 granted Dec. 16, 1952 both disclose clamps for holding rigid pipes in closely spaced parallel arrangement. The Davis patent U.S. Pat. No. 4,361,935 granted Dec. 7, 1982 discloses a flexible banding strap and an associated lock ring for clamping a pipe and an electric cable in parallel arrangement. The Hattori et al. patent U.S. Pat. No. 5,172,877 granted Dec. 22, 1992 shows a clamp for holding two or more parallel pipes in a fixed relationship.
There is a need for a pipe clamp which can be used for making a joint between a first pair of pipes having adjoining free ends and a joint between a second pair of pipes having adjoining free ends and which will exhibit a good fluid seal and high pull-apart strength.
In accordance with this invention, a band clamp is provided for connecting a first pair of pipes having adjoining pipe ends to make a first sealed joint and for connecting a second pair of pipes having adjoining pipe ends to make a second sealed joint with the first and second pairs of pipes being disposed in side-by-side, closely spaced, axially parallel relation with a lateral gap therebetween. This is accomplished by a clamp band comprising a closed loop for encircling both the first and second pairs of pipes and having a width great enough to overlap a portion of the adjoining ends of the first and second pairs of pipes. The closed loop has first and second oppositely disposed concave lobe portions spanning the gap between the pipes and a clamping mechanism is provided for drawing the lobe portions toward each other for tightening the band around the adjoining pipe ends to provide a mechanical connection and sealed joint between the adjoining ends of the first pair of pipes and between the adjoining ends of the second pair of pipes.
Further, in accordance with the invention, the band clamp is provided with a clamping mechanism comprising first and second wedge-shaped spacers disposed respectively in said first and second lobe portions with each of the spacers having an apex pointed toward the gap between the pipes, and a threaded fastener extending through the spacers and the lobe portions and being operatively connected with the spacers whereby tightening of the fastener stretches the clamp band around the periphery of the first and second pairs of pipes to provide a mechanical connection and sealed joint between the adjoining ends of the first pair of pipes and between the adjoining ends of the second pair of pipes.
Further, in accordance with the invention, the clamping mechanism includes a reaction block disposed between the lobe portions and has a cross-sectional configuration which substantially fills the space bounded by said lobe portions and by the first and second pairs of pipes.